using System;

using Org.BouncyCastle.Asn1;
using Org.BouncyCastle.Math;

namespace Org.BouncyCastle.Asn1.Pkcs
{
	public class Pkcs12PbeParams
		: Asn1Encodable
	{
		private readonly DerInteger iterations;
		private readonly Asn1OctetString iv;

		public Pkcs12PbeParams(
			byte[]	salt,
			int		iterations)
		{
			this.iv = new DerOctetString(salt);
			this.iterations = new DerInteger(iterations);
		}

		private Pkcs12PbeParams(
			Asn1Sequence seq)
		{
			if (seq.Count != 2)
				throw new ArgumentException("Wrong number of elements in sequence", "seq");

			iv = Asn1OctetString.GetInstance(seq[0]);
			iterations = DerInteger.GetInstance(seq[1]);
		}

		public static Pkcs12PbeParams GetInstance(
			object obj)
		{
			if (obj is Pkcs12PbeParams)
			{
				return (Pkcs12PbeParams) obj;
			}

			if (obj is Asn1Sequence)
			{
				return new Pkcs12PbeParams((Asn1Sequence) obj);
			}

			throw new ArgumentException("Unknown object in factory: " + obj.GetType().FullName, "obj");
		}

		public BigInteger Iterations
		{
			get { return iterations.Value; }
		}

		public byte[] GetIV()
		{
			return iv.GetOctets();
		}

		public override Asn1Object ToAsn1Object()
		{
			return new DerSequence(iv, iterations);
		}
	}
}
